If you’re planning a trip to China, here’s a tip that could save you thousands: Avoid an outfit called Sky Energy Travel, and its proprietor, May Woo.

Take it from some people who didn’t, and paid dearly. In Woo’s plant-filled travel office on the second floor of a building on Chinatown’s Kneeland Street, these mostly Chinese immigrants dropped a lot of money, along with a few illusions about their adopted country.

Mon, 68, has been here 41 years, so he thought he knew what was what. Still, when Woo offered tickets to Rangoon that were $500 cheaper than he’d seen anywhere else, he gladly paid her $4,500 in cash. Woo gave him a printed flight confirmation, but when Mon checked online, there was no booking in his name. The few times she answered his calls, Woo made promises.

“She says the tickets will be there tomorrow, next day, next week,” Mon said. “I was never cheated before.”

It can’t be of much consolation, but he has plenty of company. They began streaming into the offices of the Chinese Progressive Association a few months ago, restaurant employees and retirees desperate for help. So far, workers at the community organization have heard from more than 40 people who say Woo cheated them to the collective tune of $166,000. And there are probably more out there.

They each have a version of the same miserable story. Woo promised cheap tickets to China, took their money — quickly, cash or check only, please — gave them receipts and official-looking confirmations, even booked flights in some cases. Then, days, or even hours, before departure (some poor sods got all the way to check-in counters), they learned their tickets had been canceled, and no refunds followed.

In May, Xian Wen Li and his sister gave Woo $9,600 for a trip to Guangzhou to pick up Li’s wife and daughter. In early June, he found the tickets had been canceled. Woo assured him he was fine, that all he needed was his flight confirmation. A couple weeks later, after seeing a story about angry Sky Energy Travel customers in a Chinese-language newspaper, Li confronted Woo again, and she assured him again he’d be able to fly with no problem. His travel day came and went, with no ticket. He reported Woo to the police. When Li, a 40-year-old construction worker, demanded his money back, he said Woo told him, “You reported it and I told you not to. I’m not giving you your money back.”

“It’s a lot of money,” said Li, sitting in a CPA office with six other alleged victims last week, speaking through a translator. “Sometimes I don’t make much more than that in a year.”

In addition to the travel business, Woo had a lucrative sideline. For a few thousand dollars per person, she said she could speed immigrants’ paths to citizenship.

Bao Jean Wong’s family gave Woo $12,000 and heard nothing for six months. When they challenged her, Woo said their applications were moving along, but that the government works slowly. Woo even signed a pledge, scrawled on a ratty sheet of notepaper, promising a full refund if they heard nothing after a few months. Want to guess how that went?

Wong gave up and went to the Progressive Association.

“She offered to pay us back $2,000 each month as long as we drop everything,” said Wong, 64. But there were no payments after the first one. “Why is she still in business?. . . All our money went into her pocket.”

Telling their stories, these men and women were as amazed as they were angry. They wondered how anybody — especially an American who shares their heritage — could take advantage of immigrants like this, in the United States.

“When you’re in another country, what you know about the United States sounds really good,” said Li, the construction worker. “This is a developed and rich country. Why can things like this happen here? Why is there no government oversight or law that prevents this?”

There are laws, of course. The attorney general’s office has been investigating Woo since June, and will likely seek restitution for her victims. It could also seek more serious penalties.

But there’s no law that can keep an American, or anybody else so inclined, from preying on people’s gullibility. And that has been a harsh realization for these immigrants, who — perhaps unrealistically — expected more.

“I’ve been here 23 years, and I don’t believe it,” said a 55-year-old bartender who didn’t want his name used. “In China, I expect this. But in America?” He paid $15,000 for last-minute tickets to Hong Kong from another vendor after the ones he bought from Woo for $10,000 never materialized.

Even if Woo is punished, he and the others don’t expect to see their money again.

“We work so hard for what we make,” the bartender said. “Why isn’t some agency protecting us? Is it because we’re Chinese?”

If only injustice were so narrowly confined.

Now, to be fair, these are all allegations. At this point, all we have are the strikingly similar allegations of 40-plus people, most of whom have never seen one another before in their lives.

So on Friday, I called Woo in the hopes that she’d tell me why all of those people are mistaken.

“I don’t know what you’re talking about,” she said.

I gave Woo a few details. She took down my number. She promised she’d call me back.

Odd thing is, she never did.

Yvonne Abraham is a Globe columnist. She can be reached at abraham@globe.com.

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